I Am Recently Diagnosed Hypothyroid And Taking 50mg Of Levo???

I am recently diagnosed hypothyroid and taking 50mg of levo??? But I am still experiencing right sided pain in my jaw radiating down my neck and back. It is not present all the time but today it is bad. It is accompanied by extreme fatigue, lightheadedness and shortness of breath walking or doing the easiest task. I was just concerned about a cardiac problem.